Wavellite | |
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General | |
Category | Phosphate minerals |
Formula (repeating unit) | Al3(PO4)2(OH,F)3·5H2O |
IMA symbol | Wav[1] |
Strunz classification | 8.DC.50 |
Crystal system | Orthorhombic |
Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
Space group | Pcmn |
Unit cell | a = 9.621 Å b = 17.363 Å, c = 6.994 Å; Z = 4 |
Identification | |
Color | Green to yellowish-green and greenish blue and blue. and yellow, brown, white and colorless |
Crystal habit | Spherical, radial aggregates; striated prisms; crusty to stalactitic |
Cleavage | [110] perfect, [101] good, [010] distinct |
Fracture | Uneven to subconchoidal |
Mohs scale hardness | 3.5 - 4 |
Luster | Vitreous to resinous, pearly |
Streak | White |
Diaphaneity | Translucent |
Specific gravity | 2.36 |
Optical properties | Biaxial (+) |
Refractive index | nα = 1.518 - 1.535 nβ = 1.524 - 1.543 nγ = 1.544 - 1.561 |
Birefringence | δ = 0.026 |
Pleochroism | Weak; X = greenish; Z = yellowish |
2V angle | Measured: 60° to 72° |
Fusibility | Infusable, swells and splits on heating |
Solubility | Insoluble |
References | [2][3][4][5] |
Wavellite is an aluminium basic phosphate mineral with formula Al3(PO4)2(OH, F)3·5H2O. Distinct crystals are rare, and it normally occurs as translucent green radial or spherical clusters.[6]